End-cell switch.



J. w. ACHARD.

END CELL SWITCH.

APPLICATION FILED MAR-9,1911.

. 1,140,322. Patented May 18, 1915;

Ji /5n Hazard UNITED STATES PATENT OFFICE.

JOHN w. sexism), or PHILADELPHIA, rmsnvsnm.

h END-CELL SWITCH.

a movable contacting member coiiperates with a series of contactsconnected to intermediate points in a series of storage battery cells,and the object of my invention is to provide an" improved method ofmounting the auxiliary resistance interposed between the travelingmember and the contact points.

My invention will be more clearly understood by referencc'to thefollowing description taken in connection with the accompanyingdrawings, in which Figure 1 is a diagrammatic view of an end cell switchembodying features of my m-' vention, Fig. 2 is a section'of one of thecontact pointsv along the line A A of Fig. 1 drawn to an enlarged scale.Fig. 3 is a section of the same contact point by a plane at right anglesto the line A A.

Referring to Fig. 1, B is a storage battery connected at one end toconductor 1 of the load circuit. Several points nearthe other end of thebattery are connected to several contact points 2, 3, 4, 5 and 6 of anend cell switch. The longitudinal bar C of this switch is connected tothe other conductor 7 of the load circuit. A traveling, brush D servesto connect the bar C with any one of the points 2 to 6, according to itsposition.

The position of the brush D is controlled-by a screw E mounted inbearings and rotated by means of a handle F. Each of the switch points,for example point 3, consists of a portion 8 of conducting metal, suchas cop: per upon which the brush D rests when in full contact with theswitch point, and a.

portion 9 of comparatively high resistance material, such as carbon,firmly connected to the portion 8 but projecting on either side thereof,so as to form auxiliary high resistance contacts when the travelingbrush D is passing frompoint to point. The brush D is shown in anintermediate position between the points 4 and 5, making contact withthe auxiliary resistances between these two points,

but out of contact with the metallic portion of these points. In thisposition there is a circuit of comparatively high resistanceSpecification of Letters Patent.

across the terminals of the cell, which points 4 and 5 are connected,through which a certain amount of current will flow while the brush istraveling between these points.

"This current may be limited to any desired value by proper design ofthese auxiliary resistances.

Patented May 18, 1915. 4

Application filed'ltarch 9,- 1911. Serial No. 613,255.

In Fig. 2 is shown one method of combi'm ing the auxiliary carbonresistance with the metallic pertionofthe switch point. This metallicportion is forked at one end to receive the carbon block 9, the upperand lower portions of the fork being indicated at 8* and 8*,respectively. Firm and rigid contact between the metallic portion andthe carbon is secured by means of the bolts 10.

One of the advantages of this method of construction over that in whichthe auxiliary resistance is carried by the brush lies in the fact thatwith my improv ed method of con-' struction, the auxiliary resistance.may be varied at different points in' the switch. In connecting an endcell switch to the end cells of a storage battery, it is sometimesdesirable to include different numbers of cells between adjacent pointsat different parts of theswitch. Thus at the extreme end of the battery,it may be desirable to connect two cells between adjacent" points,whereas near the other end of the series of end cells, in order toprovide for a closer adjustment of the floating point, it may bedesirable to connect only one cell between adjacent points. This methodof connection is illusmore rigidconstruction-of these auxiliary With theimresistances, and permits the omission of the dead points heretoforeused between adjacent contact points for supporting the brush when in an1ntermediate position between the two contacts.

An additional advantage 'lies in the gradual introduction of resistanceasQthe brush the gradual reductionof resistance as'the ,recedes from oneof the main contacts, and

' high resistance contact on the brush itself,

but in this case the same auxiliary contact is subjected to theexcessive heating eifect of the current throughoutthe entire travel of.the brush, whereas with the arrangement of my invention each auxiliarycontact is used only once, as the brush travels from one end of theswitch to the other, and the heating effect is thus divided among anumber of contacts.

Having described my invention what ll claim and desire to secure byLetters Patent is i a 1. In a multiple point switch including a seriesof stationary main contact terminals spaced apart and cooperatingtherewith a traveling brush narrower than the space between saidterminals, the combination with said main terminals of auxiliarycontacts consisting of conducting blocks of comparatively highresistance rigidly attached to and in electrical contact with said mainterminals, each block extending across the corresponding terminalbeneath the contact surface thereof, and projecting on either side, theprojections being brought flush with said main contact surface, so as toform high resistance auxiliary contacts for the brush between the maincontact terminals, substantially as described.

2. In a multiple point switch, a main contact terminal forked by a slotbeneath the contact surface in combination with a conducting block ofcomparatively high resist ance rigidly fastened in the fork, andextending on either side thereof, said block being notched to receivethe fork, substantially as described. 'I v 3. In combination an end cellswitch having a series of stationary contacts spaced apart, a storagebattery divided into groups containing diflerent numbers of cells,connections between the adjacent switch contacts and the adjacent groupsand stationary conducting members of comparatively high resistancearranged between the contacts and respectively electrically connectedthereto, said members differing in resistance between themselves tocorrespond with the different numbers of cells in said groups.

In testimony whereof I have hereunto signed my name.

- JQHN l V. ACE-FLARE). V'Vitnesses J. H. Terror, T. L. Hamamnsnnr.

